1. Costing of Pressure Vessels 1. Quick Method: simple cylindrical vessels 2. Costing by Weight: more complex shapes

2. Quick Method

3. Pressure and Material Factors: F BM =f(F P xF M ) go to Figure 5-46

4. Bare Module Factors

5. Tower Packings

6. Trays

7. Cylindrical Vessel Cost Cost of internals added onto vessel cost for packed or trayed columns. Heated vessels cost more. Pressure Material

8. What about more complex shapes? Estimate cost based on weight of vessel

10. Contributions to Weight Vessel shell (cylindrical or conic sections) Vessel heads Cost of manways, skirts, nozzles Cost of auxiliaries - platforms, ladders, handrail Total weight = (weight of shell + weight of heads)x1.1 (for flanges, auxiliaries etc.)

11. Hoop Stress Calculation Pressure stress < tensile strength of shell t R p S = maximum tensile stress (Pa) C s = corrosion allowance (m) t = wall thickness (m) p = gauge pressure (Pa) R = vessel radius (m) (Ulrich pp 250)

12. Tensile Stress for Metals Strong function of temperature!

13. Vessel Heads Singh, 1990 (Course Pack) Hemisphere Ellipsoidal Torispherical (Most common) Conical Sphere Need to match head thickness to shell thickness.

14. Torispherical Heads L=crown or dish radius r=knuckle radius R=vessel radius

15. Torispherical Heads Singh, 1990: SE = effective stress = 0.9S p, t, C s as before L = dish radius r = knuckle radius M = factor Typically: L=2R; r=R/8, so